The subject matter disclosed herein relates to gas turbines, and more specifically, to seals within turbines.
In general, gas turbine engines combust a mixture of compressed air and fuel to produce hot combustion gases. The combustion gases may flow through one or more turbine stages to generate power for a load and/or compressor. The combination of hot gases and high pressures can cause stress and wear of components in the turbine. To reduce the stress and wear, cooling gases flow through parts of the turbine, such as the sections between wheels, or the interior of turbine blades. Between each stage, a pressure drop may allow some leakage of the combustion gases to sections designated for cooling gases, or the cooling gases may leak into sections designated for combustion gases. Fluid leakage can reduce the efficiency of the turbine, reduce uniformity between turbines (which can cause uncertainty in a service schedule), or can allow wear of the turbine components, among other problems. Seal assemblies may be disposed between the stages to reduce fluid leakage between stages. Unfortunately, the seals may be subject to stresses, such as thermal stresses, which may bias the seals in axial and/or radial directions, thereby reducing effectiveness of the seals. To reduce the stresses on the seal assemblies, the assemblies may be placed away from the path of the combustion gases. This arrangement, however, may cause additional leakage between the seal assembly and a nozzle that is used to direct the combustion gases. Furthermore, the seal assemblies may extend the distance between turbine stages, which can cause an increase in the overall cost of the turbine.